Heat exchanger



1.1 is a bottom, front, and right side perspective view of a heat exchanger;

1.2 is a top, front, and right side perspective view of the heat exchanger of FIG. 1.1;

1.3 is a top, rear, and left side perspective view of the heat exchanger of FIG. 1.1 with a portion removed for completeness of the disclosure;

1.4 is an enlarged and partial rear and left side perspective view of the heat exchanger of FIG. 1.1 with a portion removed for completeness of the disclosure;

1.5 is a top plan view of the heat exchanger of FIGS. 1.1; and

1.6 is a left side elevational view of the heat exchanger of FIG. 1.1 with a portion removed for completeness of the disclosure;

2.1 is a bottom, front, and right side perspective view of alternate embodiment of a heat exchanger;

2.2 is a top, front, and right side perspective view of the heat exchanger of FIG. 2.1;

2.3 is a top, rear and left side perspective view of the heat exchanger of FIG. 2.1 with a portion removed for completeness of the disclosure;

2.4 is an enlarged and partial rear and left side perspective view of the heat exchanger of FIG. 2.1;

2.5 is a top plan view of the heat exchanger of FIGS. 2.1; and

2.6 is a left side elevational view of the heat exchanger of FIG. 2.1 with a portion removed for completeness of the disclosure;

3.1 is a bottom, front, and right side perspective view of another alternate embodiment of a heat exchanger;

3.2 is a top, front, and right side perspective view of the heat exchanger of FIG. 3.1;

3.3 is a top, rear and left side perspective view of the heat exchanger of FIG. 3.1 with a portion removed for completeness of the disclosure;

3.4 is an enlarged and partial rear and left side perspective view of the heat exchanger of FIG. 3.1;

3.5 is a top plan view of the heat exchanger of FIG. 3.1; and

3.6 is a left side elevational view of the heat exchanger of FIG. 3.1. 

CLAIM The ornamental design for a heat exchanger, as shown and described. 